DE69531658T2 - Use of coated paper or cardboard as a recyclable and repulpable giant wrap - Google Patents

Description

Field of the Invention

The invention relates generally on the use of recyclable and re-unlockable, coated paper and of recyclable and re-unlockable, coated cardboard as giant wrapping paper, the water resistance, grease resistance and has moisture vapor barrier properties. The giant wrapping paper comprises a substrate having at least one surface with a Base layer and at least one additional layer over the Base layer is coated, both as wax-free, polymeric Dispersions on aqueous Base to be applied. The dispersion coatings on aqueous Bases are more easily unlocked and recycled than conventional polyethylene or wax coatings.

Background of the Invention

Polyethylene films and wax coatings, which are generally laminated or applied to paper, become large Dimensions at Packaging applications used to protect products from moisture protect and water resistance or fat resistance provide. Recycling packaging, polyethylene films and contain wax coatings, but is limited and expensive, for this unlocking special equipment are necessary, and various procedural steps are required are before such a slurry can enter a recycling stream along with office waste paper. additionally this does not include polyethylene films and some wax coatings degraded when the packaging is composted. These problems will be encountered in special packaging application areas, e.g. B. if such coatings for the production of giant wrapping paper be used.

Conventional giant wrapping papers are typically a multi-layer product that is a medium Has polyethylene layer between two layers of paper. polyethylene is used in ream wrapping papers to create an effective barrier across from To provide water vapor (moisture) which is a ripple of paper can cause feed errors and jams in copying machines or printing presses. This multilayered Giant wrapping paper cannot be easily recycled become. landfill and waste incineration plants are the usual Ways to dispose of polyethylene packaging materials. alternative other coatings and coating systems are known for this, which do not contain polyethylene, but the degree of moisture resistance to provide the for Giant wrapping paper is necessary. For example, U5-A-4,117,199 discloses to Gotoh et al. a reclosable coated paper, which contains a synthetic rubber latex and a wax emulsion. Coatings like Vapo-Stop manufactured by Cham-Tenero Paper Mills, Inc., Cham, Switzerland closes a styrene-butadiene polymer, wax and acrylic polymer components one, the coated substrates have a moisture resistance to lend. However, these systems contain a high wax load, whereby the wording for recycling as office waste and unlocking for the production of white Paper becomes unacceptable.

So it would be desirable to have an alternative to conventional ones To find polyethylene films and coatings containing wax which has comparable moisture barrier properties, but also the additional Advantage of recyclability and re-opening having.

EP-A-0375924 discloses recyclable Papers that have at least two on top of each other have arranged layers that differ from aqueous dispersions of polyvinylidene chloride, Derive polyvinyl acetate, etc., which the coated paper against water vapor resistant do.

US-A-2,392,972 to Cheyney the surface treatment of paper with a coating of vinylidene chloride-vinyl chloride copolymers, to make a coated paper that is permeable to resistant to water vapor is. Other representative Patents stipulating the use of polyvinylidene chloride To provide water vapor resistance to paper, include the following a: US-A-3,476,587 to Demol et al. which discloses compositions comprising two vinylidene chloride copolymers - one of which one is hard, the other is soft - to waterproof a substrate and US-A-3,423,232 to Reinhard et al of flat substrates with aqueous Dispersions disclosed that 80-98% Include vinylidene chloride polymers as the lower and upper layers.

US-A-3,306,766 to Hathaway et al. discloses a resin coated packaging product, preferably a paper-based film, the exposed surface with a halogen ethylene polymer resin such as Saran is coated and that an intermediate flexible base coating made from extruded ethylene-lower alkyl acrylate copolymer resin having. The halogen ethylene polymer resins, e.g. B. Saran, are opposed to that Passage of water vapor resistant and close at least 60% by weight of polyvinylidene chloride resins.

From the prior art mentioned above can be seen that coatings, the vinylidene chloride copolymers lock in, to provide a moisture barrier layer are known however, according to the state no technique for the direct application of these coatings on a porous substrate provided. It would be desirable, an advantage over achieve known applications by using wax-free, aqueous coatings provides that are applied directly to a substrate surface in order to Water and water vapor resistance properties to lend with those of conventional polyethylene or Wax coatings are comparable, but easier to re-open and be recycled. The present invention relates on the provision of such recyclable and reclassifiable coatings, to produce a coated paper product that is used as giant wrapping paper can be used. The waterborne coatings of the invention represent an alternative to conventional polyethylene coatings and wax coatings and an advantage over state of the art, since the coated paper without any special Flotationsgerätschaften can be easily unlocked, which are necessary when a polyethylene film is opened again. The coatings on watery Base disperse in water, which allows the paper fibers easy for recovered a reuse become. The coatings according to the invention are in contrast to wax coatings together with office waste paper reopened and recycled to a white paper high quality manufacture.

An object of the invention is therein, a recyclable and reclassifiable paper raw material to provide for use as ream wrapping paper, water resistance, grease resistance and has moisture barrier properties and without dependency easily recycled by special reclamation equipment becomes.

Disclosure of the invention

More specifically, the present invention relates to the use of a recyclable and re-openable coated paper or a reusable and re-openable coated paperboard coated on at least one surface with a base layer as ream wrapping paper and at least one additional layer over the base layer, the base layer and the additional layer are both wax-free and are applied to the paper or cardboard as water-based dispersions consisting essentially of a single polymer selected from the group consisting of acrylic polymers, acrylic copolymers, polyvinyl acetate, polyvinyl alcohol, ethylene Vinyl acetate, polyvinyl chloride, styrene-butadiene copolymers, polyvinylidene chloride and its copolymers or starch, the base layer and the additional layer optionally comprising thickeners, defoamers or antifoams, crosslinking agents, gels may include additive additives, mold release agents and anti-blocking agents; and wherein the base layer and the additional layer form a non-porous continuous film on the substrate which is water resistant and has a water vapor transmission rate in the range of 0.8 to 7 g / 645.2 cm ² (100 in ² per 24 h).

Preferred embodiments of the invention are from the subclaims seen.

In the present invention these goals, as well as others that are apparent, generally through coating at least one surface of a substrate with a Base layer and at least one additional layer over the Base layer reached, both as polymeric dispersions on aqueous Base to be applied. Alternative embodiments include that Apply at least one additional layer.

Typically, the coatings include Dispersions with a solids content greater than 20% and a viscosity in the range from 20 to 1000 mPa · s (CP).

In a preferred embodiment the base layer comprises an acrylic-modified poly (ethyl acrylate) latex, and the additional Layer comprises polyvinylidene chloride or copolymers thereof. In another preferred embodiment, the base layer comprises and the additional Layer of polyvinylidene chloride or copolymers of the same. Additionally can in any embodiment at least one more additional Layer of the same materials can be applied.

The base layer can additionally Pigments or mineral fillers how - but not limited to - aqueous dispersions of clay, calcium carbonate or mica. Other additional Components of the coatings can Thickeners, defoamers or anti-foaming agents, pigments, crosslinking agents, lubricant additives, Include mold release agents and anti-blocking agents.

Substrates used in the invention are cellulosic materials and include a variety of coated and uncoated types of paper and cardboard, including bleached or unbleached hardwood or softwood forms, untreated or recycled and clay-coated or uncoated forms of paper and cardboard. The basis weight of the substrates ranges from 9.06 to 67.95 kg / 278.71 m ² (20 to 150 lb per 3000 sq. Ft.), And the thickness ranges from 0.102 to 0.635 mm (0.004 to 0.025 inch) , A preferred substrate is paper and it is selected from the group consisting of bleached Paper, clay-coated bleached paper, unbleached paper, or recycled paper.

The coatings are applied to the substrate surface as aqueous dispersions. The coatings are dried on the substrate surface to form a non-porous, continuous film on the substrate that is resistant to water and water vapor. The water vapor permeability rates of the coated raw materials are in the range of 0.8 to 7 g / 100 sq. in./24 h (100 sq. in. = 645.2 cm ² ) and preferably between 1 and 3 g / 100 sq. in./24 h. Depending on the composition of the base layer, the base layer is either partially dried or completely dried before the additional layer is applied.

The individual layers applied each have dry layer weights in the range of 0.453 to 3.624 kg / 278.71 m ² (1 to 8 lb / 3000 sq. Ft.). The total dry film weights on the substrates range from 0.453 to 7.248 kg / 278.71 m ² (1 to 16 lb / 3000 sq. Ft.).

The recyclable and re-unlockable, coated Paper stock of the invention is formed into a package, i.e. H. a giant wrapping paper that has water resistance, moisture vapor barrier properties and fat resistance having. In preferred applications, the coating corresponds on watery Base of a moisture vapor barrier layer that is in the inner Structure of the packaging is localized, which prevents the enclosed Materials such as copy paper warp or curl.

The wax-free coatings of the Invention are more easily unlocked and reused than conventional ones Polyethylene or wax coatings. The coated paper stock can advantageously directly a recycling stream of office paper waste be given, regardless of special equipment, around a white High quality paper to create.

Other purposes, features and benefits of the present invention will become more detailed from the following Description of the best mode for carrying out the invention, when viewed with reference to the drawings as follows becomes.

Brief description of the drawings

The 1 Figure 3 is an illustration of a recyclable and re-openable coated paper stock used in accordance with the invention;

the 2 Figure 3 is a schematic diagram of the manufacturing process;

the 3 to 8th are diagrammatic explanations of WVTR values as a function of time according to Examples 1 to 6, and

the 9 to 11 are diagrammatic explanations of WVTR values as a function of the time of a polymer / wax-coated substrate according to Example 7, 80%, 70% and 60% of the wax component being removed from the coating.

Detailed description of the preferred Ausführunsgsform

aqueous Barrier layers and related manufacturing processes are disclosed in WO-A-94/26513.

Those in the present invention Compositions used are modifications and improvements of these formulations and make composition coatings ready that are free of any wax component and special used to make coated paper stock which have comparable barrier properties as conventional polyethylene or wax coatings. These coatings become lighter reopened and recycled as conventional Coatings and can given directly to a recycling stream of office waste paper, without special equipment dependent to be a white High quality paper manufacture.

2 is a schematic diagram of the general manufacturing process. In the first step 18 a base layer is applied to at least one surface of a substrate.

The base layer essentially seals the porous substrate surface. The base coat is generally applied using conventional coating equipment such as gravure, flexographic, air knife, doctor or spiral scraper coaters. Depending on the composition of the base layer, the base layer is either partially dried or completely dried before the additional layer is applied using forced air ovens. The extra layer 22 is applied over the base layer and dried 24 to form a non-porous continuous film, which the coated paper stock 26 Gives barrier properties. The furnace temperatures and the line speeds are determined by the selection of the base layer and additional coating formulations (e.g.% solids), the substrate (e.g. base weight, absorption capacity) and the properties of the equipment. Adequate drying conditions, such as oven temperature, line speed, etc., are required to block the roll and blow out and to prevent the coating from cracking during winding of the coated substrate.

Like in the 1 is shown, the recyclable and reclassifiable paper raw materials comprise a substrate 12 , on which there is a base layer on at least one surface 14 is applied, and at least one additional layer 16 that is applied over the base layer. The base layer and the additional layer or the additional layers are polymeric emulsions or dispersions on an aqueous basis. The terms "emulsions" and "dispersions" are often used interchangeably. Hackh's Chemical Dictionary, 4th ed., 1969 defines a dispersed system (or a dispersion) as an "obviously homogeneous substance consisting of a microscopically heterogeneous mixture of two or more finely divided phases (solid, liquid or gaseous), e.g. liquid and liquid, solid and gaseous, etc. " An emulsion is defined as "a suspension of one liquid in another liquid" and is considered to be a type of dispersion. To describe coatings in the specification, the term "dispersion" is typically used herein. At ambient temperatures, the coating compositions are generally solid / liquid dispersions, but the compositions can also be emulsions or liquid / liquid dispersions.

The base layer and the additional Layer or the additional Layers are free of any wax component. The base layer essentially seals and reduces the substrate surface from the intrusion of the additional Layer in the substrate. The coatings comprise a dispersion on watery Base of a polymer selected from the group consisting of acrylic polymers, acrylic copolymers, Polyvinyl acetate, polyvinyl alcohol, ethylene vinyl acetate, polyvinyl chloride, Styrene-butadiene copolymers, polyvinylidene chloride and their copolymers or strength.

The solids content of each coating layer is generally greater than 20%, and preferably 40-55%, to give sufficient dry addition levels ranging from 1 to 8 lb / 3 MSF and 0.453 to 3.624 kg / 278.71 m ² to reduce drying requirements. Preferably, the base layer is in the range of 0.906 to 1.585 kg (2.0 to 3.5 lbs) and the additional layer is between 1.585 and 2.26 kg (3.5 to 5.0 lbs) per 278.71 m ² (3000 MSF). The total dry coating weights on the substrate surface range from 0.453 to 7.248 kg / 278.71 m ² (1 to 16 lbs. Per 3000 sq. Ft.). The viscosity of the coating is preferably in the range from 20 to 1000 mPa · s (cP). The low viscosities of the compositions result in little penetration into the substrate surface, but this is sufficient to adhere or bind the coating to the substrate surface.

Typically, at least one base layer is applied to the substrate surface, but in alternative embodiments, at least one additional layer of the same material can be applied before the additional layer is applied. A single base layer on the substrate surface imparts moisture barrier properties to the substrate, but the presence of multiple coating layers increases the barrier properties. The water vapor permeability rates of the coated raw materials are in the range from 0.8 to 7 g / 100 in ² per 24 h and preferably between 1 and 3 g / 100 in ² per 24 h (100 in ² = 645.2 cm ² ).

The coatings are called aqueous dispersions on the substrate surface applied. The coatings are dried on the substrate surface, to form a non-porous continuous film on the substrate, the opposite Resistant to water and steam is. Dependent on from the composition of the base layer, the base layer becomes either partially or completely dried before the additional Layer is applied to ensure proper adhesion.

In a preferred embodiment the base layer comprises an acrylic modified poly (ethyl acrylate) latex, and the additional Layer comprises polyvinylidene chloride or copolymers thereof. During the The method of making this embodiment is critical that the base coat is partially dried if not the case is typically incomplete liability the additional Coating layer. In another preferred embodiment include both the base layer and the additional layer Layer of polyvinylidene chloride or copolymers of the same. In the process of Manufacture of this embodiment the base layer becomes complete dried before the additional layer is applied, which consists of the same material. This results in multiple thin Coating layers, which advantageously have the barrier properties of the coated substrate. additionally this can be done in any embodiment at least one more additional Layer of the same coating materials can be applied.

The materials from which the coatings are made are generally available under different trade names and from different manufacturers. Representative polymers or dispersions that can be used include - but are not limited to them - the following: Airflex ^® 100 HS, which is an ethylene-vinyl acetate emulsion water-based, from Air Products and Chemicals, Inc. , Allentown, Pennsylvania 18195; PRECOAT 44, which is an aqueous-based acrylic (polyethylene acrylate latex) emulsion available from Michelman, Inc., 9080 Shell Road, Cincinnatti, Ohio, 45236-1299; SERFENE ^® 121, which is a polyvinylidene chloride (PVDC) latex, sold by Morton International Specialty Chemicals Group, 333 West Wacker Drive, Chicago, Illinois, 60606 to 1292 is; and GEON ^SM 650X18 LATEX, which is an aqueous-based polyvinylidene chloride available from BF Goodrich, 9911 Brecksville Road, Cleveland, Ohio, 44141-3247. The physical characteristics and properties of these commercially available materials are further described in the technical data sheets referred to herein.

The polymer dispersions mentioned above can combined with other materials to make the base layer special To give properties. For example, a pigment or a mineral Filler like - but without limited to this to be - aqueous dispersions clay, calcium carbonate or mica are inserted into the coating, for improved leveling, improved smoothness and Sealing a rough or porous To yield substrate.

Other additional components of the coatings can Thickeners, defoamers or Anti-foaming agents, crosslinking agents, lubricant additives, mold release agents and include anti-blocking agents.

Substrates used in the invention include a variety of coated and uncoated types of paper and paperboard, including bleached or unbleached forms, hardwood or softwood forms, untreated or recycled and clay-coated or uncoated forms of paper and cardboard. For ream wrapping paper applications, the substrate is preferably some form of bleached white paper. The basis weight of the substrates is in the range of 9.06 to 67.95 kg / 278.71 m ² (20 to 150 lbs per 3000 sq. Ft.) , and the thicknesses range from 0.102 to 0.635 mm (0.004 to 0.025 inch). For giant wrapping paper applications, the basis weight - if the substrate is bleached paper - is preferably 9.06 to 40.77 kg / 278.71 m ² (20 to 90 lbs per 3000 sq. Ft.), And for a clay-coated paper- Substrate preferably 27.18 kg / 278.71 m ² (60 lbs per 3000 sq. Ft.).

The coatings on watery Base as watery Dispersions by any coating process used for coatings on watery Base is suitable, applied to the substrate. Examples of suitable ones Close coating process conventional methods such as air knife coating, knife coating, Measuring roller coating, gravure coating, rod coating, curtain coating and spraying. Generally there is some kind of drying at elevated temperature required to make the waterborne coatings with an acceptable Drying production speed. Partial drying preferably occurs at temperatures in the range of 104.4 ° C to 121.1 ° C (220-250 ° F) and a complete Dry at 176.7 ° C up to 198.9 ° C (350-390 ° F). suitable Close drying process - but without limited to the same to be - hot air drying, Infrared drying and drying by contact with a heated drum on.

In a preferred embodiment, the substrate is a calendered, bleached paper with a basis weight of 22.65 kg / 278.71 m ² (50 lb / 3 MSF). The base layer is an acrylic latex emulsion with a solids content of 44% and a viscosity of 250 to 450 mPa · s (cP). The basecoat is applied using a spiral scraper application, giving a dry addition content of 0.453 to 1.58 kg / 278.71 m ² (1 to 3.5 lb / 3MSF). The base coat is partially dried by passing it through hot air ovens set at 121.1 ° C (250 ° F) before the additional coat is applied. The additional layer is preferably a polyvinylidene chloride copolymer latex. Generally, this additional layer has a viscosity of 40 to 75 mPa · s (cP). The additional layer is applied at a dry addition level of 0.453 to 3.624 kg / 278.71 m ² (1 to 8 lb / 3MSF) using a spiral scraper arrangement. The coated substrate is again passed through hot air ovens set at 350 ° F (176.7 ° C) to cure the coating. Additional coating layers can be added. The total dry addition levels for all coating layers range from 0.906 to 7.25 kg / 278.71 m ² (2.0 to 16 lb / 3 MSF).

Set the following examples 1 to 6 the different coating formulations and working methods represents the manufacture of the coated paper stocks of the invention be used. Example 7 explained the impact on barrier properties after removal parts of the wax component from an acrylic / wax emulsion coating. The coating weights listed are in the examples Dry coating weights unless otherwise stated becomes. These examples are purely representative and are not conclusive all of the possible embodiments of the invention.

The water vapor permeability rate and water resistance (30 min Cobb test) of the examples were measured. Additionally the fat resistance (kit grade) was also measured in Example 7. These functional properties were determined according to the following procedures certainly.

The water vapor transmission rate ("WVTR") was determined using the TAPPI method T464 om-90, which specifies that the "gravimetric determination of the water vapor transmission rate of film materials at high temperature and humidity" provides a means to test the ability under standardized conditions of a material to provide protection against unwanted moisture changes due to the transmission of water vapor through the material. A permeability rate of 3 g / 100 in ² per 24 h (100 sq. In. = 645.2 cm ² ) indicates better protection for packaged ingredients against moisture loss or moisture gain than one Permeability rate of 10 g / 100 in ² per 24 h (100 sq. In. = 645.2 cm ² ).

The Cobb test, TAPPI method T442 om-84, determines how much water is absorbed by the paper and cardboard in a given period of time. Generally, this measurement is useful for sized materials to determine the water resistance properties of the water-based coatings. The lower the result, the more water-resistant the material. A material with a Cobb of 3.45 g / 100 in ² (100 in ² = 645.2 cm ² ) in 10 minutes is less water-resistant than a material with a Cobb of 0.03 g / 100 in ² (100 in ² = 645.2 cm ² ) in 10 minutes. The time period of the test depends on the substrate to be tested. Sized materials are tested for 120 seconds, while a heavily coated, corrugated sample can be tested over a 16 hour period. The coated substrates of the invention were tested over a 30 minute period.

The one for measuring fat resistance The method used is the kit test, USEFUL METHOD 557. This test measures fat resistance of paper and cardboard materials used during the wet end with fluorochemical Sizing agents are treated. This test is not intended to the fat resistance of Measure continuous foils, but the results obtained are useful and are accepted as an indication of the general fat resistance. The fat resistance the better the higher is the value of the kit test.

example 1

The substrate is a bleached, white 22.65 kg / 278.71 m ² (50 lb / 3MSF) kraft paper. The base layer comprises an acrylic modified poly (ethyl acrylate) latex (44% solids, viscosity 250 to 450 mPas (cP)), available as PRECOAT-44 from Michelman, Inc., 9080 Shell Road, Cincinnatti, Ohio, 45236 -1299. The additional layers include either precoat 44 or a polyvinylidene chloride latex (50% solids, viscosity 40 to 75 mPa.s (cP)) available as SERFENE ^® 121 from Morton International Specialty Chemicals Group, 333 West Wacker Drive, Chicago, Illinois , 60606-1292.

The base layer is applied to the substrate and gives dry addition levels in the range of 0.906 to 1.58 kg / 278.71 m ² (2.0 to 3.5 lbs / 3MSF). A second layer comprising PRECOAT-44 was similarly applied to the base layer and gives dry addition levels in the range of 0.906 to 1.58 kg / 278.71 m ² (2.0 to 3.5 lbs / 3MSF). This second layer was partially dried by passing it through hot air ovens set at 104.4 ° C to 122.1 ° C (220-250 ° F), followed by the application of an additional layer comprising Serfene ^® 121 , This coating gives dry addition levels in the range of 1.58 to 2.26 kg / 278.71 m ² (3.5 to 5.0 lbs / 3MSF). Note that the second layer is partially dried to cause the additional coating layer to adhere. The coated substrate is passed through hot air ovens having temperatures in the range of 176.7 ° C to 198.9 ° C (350-390 ° F) to cure the coating. The total coating weight on the substrate surface is 3.73 kg / 278.71 m ² (8.24 lbs / 3 MSF).

The aqueous coatings were by rod coater - with Hot air flotation ovens after each Coating station in the temperature ranges specified above - applied. An air flow of ambient temperature was used to to cool dry endless web, in combination with a chill roll to block to prevent in the finishing roller.

The 3 illustrates in a diagram the WVTR values as a function of time for the coated substrate in this example, and these are also summarized in Table I below. The average WVTR for this coating is 2.3 g / 100 sq. in. per 24 h (100 sq. in. = 645.2 cm ² ).

Example 2

The same materials and the same procedure as in Example 1 were used, except that the total coating weight on the substrate surface is 9.8 g / 3 MSF (3 MSF = 278.71 m ² ).

The 4 illustrates in a diagram the WVTR values as a function of time for the coated substrate in this example, and these are also summarized in Table I below. The average WVTR for this coating is 1.3 g / 100 sq. in. per 24 h (100 sq. in. = 645.2 cm ² ).

Example 3

The substrate is 22.65 kg / 278.71 m ² (50 lb / 3MSF) recycled paper. The base layer comprises an ethylene-vinyl acetate emulsion based on water (55% solids, viscosity of 250 to 450 mPa · s (cP)) available as Airflex ^® 100 HS from Air Products and Chemicals, Inc., Allentown, Pennsylvania 18,195th The additional layers include either Airflex ^® 100 HS or a polyvinylidene chloride latex (50% solids fe, viscosity from 40 to 75 mPa.s (cps)) that serves as SERFENE ^® 121 Morton of Morton International Specialty Chemicals Group, 333 West Wacker Drive, Chicago, Illinois, 60606-1292 is available.

The base layer is applied to the substrate and gives dry addition levels in the range of 0.906 to 1.58 kg / 278.71 m ² (2.0 to 3.5 lbs / 3MSF). A second layer comprising Airflex ^® 100 HS, was applied in a similar manner to the base coat layer to give a dry add-on levels in the range from 0.906 to 1.58 kg / m ² 278.71 (2.0 to 3.5 lbs / 3MSF). This second layer was dried, followed by the application of an additional layer comprising Serfene ^® 121. This coating gives dry addition levels in the range of 1.58 to 2.26 kg / 278.71 m ² (3.5 to 5.0 lbs / 3MSF). The coated substrate is passed through hot air ovens having temperatures in the range of 176.7 ° C to 198.9 ° C (350-390 ° F) to cure the coating. The total coating weight on the substrate surface is 5.1 kg / 278.71 m ² (11.25 lbs / 3 MSF).

The aqueous coatings were applied by rod coating and coated with hot air flotation ovens each coating station dried. An airflow of ambient temperature was used to cool the coated, dry web, and in combination with a chill roll, to prevent jamming in the finishing roller.

5 illustrates the WVTR values versus time for the coated substrate in this example and is also summarized in Table I below. The average WVTR for this coating is 1.3 g / 100 sq. in. per 24 h (100 sq. in. = 645.2 cm ² ).

Table I Examples 1 to 3 WVTR measurements as a function of time (WVTR - g / 100 sq. In. Per 24 h - 100% relative humidity / 90 ° F)

(100 sq. In. = 645.2 cm ² ; 90 ° F = 32.2 ° C)

Example 4

The substrate is bleached white paper (machine satin) with 22.65 kg / 278.71 m ² (50 lb / 3MSF). The coatings comprise a polyvinylidene chloride latex (50% solids, viscosity from 40 to 75 mPas (cP)), which as Morton International Serfene ^® 121 from Morton International Specialty Chemicals Group, 333 West Wacker Drive, Chicago, Illinois, 60606- 1292 is available. In this example, three coating layers are applied to the substrate.

The base layer is applied to the substrate and gives dry addition levels in the range of 0.906 to 1.58 kg / 278.71 m ² (3.5 to 5.0 lbs / 3MSF). Two additional coating layers of the same material are applied and each result in dry addition contents in the range from 0.906 to 1.58 kg / 278.71 m ² (3.5 to 5.0 lbs / 3MSF). The coated substrate is passed through hot air ovens having temperatures in the range of 176.7 ° C to 198.9 ° C (350-390 ° F) to cure the coating. The total coating weight on the substrate surface is 5.07 kg / 278.71 m ² (12.6 lbs / 3 MSF).

The aqueous coatings were applied by rod coating and coated with hot air flotation ovens each coating station dried. An airflow of ambient temperature was used to cool the coated, dry web, and in combination with a chill roll, to prevent jamming in the finishing roller.

6 illustrates the WVTR values versus time for the coated substrate in this example and are also summarized below in Table II. The average WVTR for this coating is 1.4 g / 100 sq. in. per 24 h (100 sq. in. = 645.2 cm ² ).

Example 5

The same materials and procedures as in Example 4 were used, except that the total coating weight on the substrate surface is 12.4 g / 3 MSF (3 MSF = 278.71 m ² ).

The 7 illustrates the WVTR values versus time for the coated substrate in this example, and are also summarized below in Table II. The average WVTR for this coating is 1.3 g / 100 sq. in. per 24 h (100 sq. in. = 645.2 cm ² ).

Example 6

The same materials and the same procedure as in Example 4 were used, except that the total coating weight on the substrate surface is 12.3 g / 3 MSF (3 MSF = 278.71 m ² ).

The 8th illustrates the WVTR values versus time for the coated substrate in this example and are also summarized below in Table II. The average WVTR for this coating is 1.4 g / 100 sq. in. per 24 h (100 sq. in. = 645.2 cm ² ).

Table II Examples 4 to 6 WVTR measurements as a function of time (WVTR - g / 100 sq. In. Per 24 h - 100% relative humidity / 90 ° F)

(100 sq. In. = 645.2 cm ² ; 90 ° F = 32.2 ° C)

Example 7 (not according to the invention)

Moisture resistant coatings typically contain high levels of wax to achieve moisture resistance. The wax in the coatings of this type, although typically re-openable, leaves a waxy residue, ie sticky residues, which are unacceptable in the manufacture of fine white recycled paper. In addition, the wax component is referred to as an "active ingredient" and provides the barrier properties in these coatings so that removing or reducing the amount of wax reduces the effectiveness of these coatings. In this example and in the 9 to 11 explains what happens when 80% to 60% of the wax component is removed from a coating formulation consisting of an acrylic / wax emulsion coating.

The acrylic / wax emulsion coating, which is used in this example is as VaporCoat by Michelman, Inc. 9080 Shell Road, Cincinnatti, Ohio, 45236-1299. The emulsion typically has 44% solids and a viscosity in the range from 800 to 1200 mPa · s (cP) on. The wax component normally makes up 40% of the emulsion out. In this example, modifications to the coating were made making them the same 20%, 30% and 40% of the wax component contained, which is normally found in the coating, accordingly the wax content reduced by 80%, 70% and 60%.

A base layer was applied to three samples of a 14 pt. Solid, bleached sulfite substrate (A, B and C), which contained an ethylene-vinyl acetate emulsion on an aqueous basis (55% solids, viscosity from 250 to 450 mPa · s (cP )), which is available as Airflex ^® 100 HS, then an additional layer of the modified acrylic / wax (VaporCoat) coating was applied, with 80%, 70% and 60% of the wax component removed from the formulation ,

The aqueous base layer and the modified VaporCoat layers were applied by knife coating and dried in a hot air oven after the application of each coating. The 9 to 11 illustrate the WVTR values as a function of time for samples A, B and C, respectively, and are also listed below in Table III. In addition, the samples were examined by the 30 minute Cobb and 3 M kit tests, the results of which are given in Table IV below. The Cobb test is a measure of water resistance and WVTR is a measure of moisture resistance. In both tests, the higher the numerical values of the test result, the worse the barrier property.

Table III Example 7 WVTR measurements versus time (WVTR - g / 100 sq. In. Per 24 h - 100% relative humidity / 90 ° F)

(100 sq. In. = 645.2 cm ² ; 90 ° F = 32.2 ° C)

Table IV Summary of the junction properties of Example 7

As shown in Tables III and IV, it can be seen that the larger the removed component of the wax component, the more the barrier properties, ie the WVTR values, decrease. For example, in sample A, in which 80% of the wax component has been removed, the average WVTR is 10.477 g / 100 sq. in per 24 h, while in sample C, where only 60% of the wax component was removed, the average WVTR is 7.366 g / 100 sq. in per 24 h. The advantage of the coatings according to the invention is obtained by providing wax-free coatings with water vapor transmission rates in the range from 0.8 to 7 g / 100 in ² per 24 h, and preferably between 1 and 3 g / 100 sq. in per 24 h (100 sq. in. = 645.2 cm ² ). In addition, the lack of a wax component in the coatings of the invention allows the coated substrates to be disrupted and recycled into high quality white paper.

repulpability and recyclability of coatings according to the invention

Generally, polyethylene films and coatings used in paper-based packaging, to provide barrier properties, but their presence restricts the unlockability of packaging in mills one, the costly separation and screening equipment have. It is well known in the industry that with polyethylene or wax coated materials versus a re-digestion process are problematic unless expensive sieve classification and cleaning equipment be used. Even with these devices, some pieces of the Coating through the paper formation area and affect the running ability. Additionally is the fiber yield from polyethylene or wax-coated products reduced, because the fiber often sticks to the coating and is removed in the sieve classification process.

The coated paper raw materials, which are used as ream wrapping paper, can be re-opened without special equipment and without special processing, especially at elevated temperatures and pH. The aqueous barrier films of the coatings can be easily split in the hydrapulper under standard conditions of pH 7 to 11 and 21.9 ° C to 60 ° C (70-140 ° F). Thieves Layers easily disintegrate in an alkaline medium to produce a slurry that contains paper fibers and particles of the coating that are devoid of any wax component. This slurry is easily introduced directly into a recycling stream of office waste paper. Conventional paper making techniques are used to convert this combined recycling stream into white paper. The wax-free coatings are easier to open up and recycle than conventional polyethylene or wax coatings without being dependent on special equipment to produce high quality white paper.

The coated paper or the coated cardboard can be made by conventional methods without special activities recycled to remove polyethylene or wax coatings. The coatings on watery Base are split up and dispersed with the paper fibers, when the material is passed through a standard hydrapulper.

The reopened paper raw materials can through regular cleaning equipment can be recycled and without any problems by conventional Paper machines are directed. The wax-free coatings result in an increased recyclability in the production of high quality white paper of the coated materials compared to conventional coatings.

Claims (10)

Use of recyclable and re-unlockable, coated paper or of reusable and re-unlockable, coated cardboard, which has at least one surface with a base layer ( 14 ) and at least one additional layer ( 16 ) over the base layer ( 14 ) are coated as ream wrapping paper, the base layer ( 14 ) and the additional layer ( 16 ) are both wax-free and on paper or cardboard ( 12 ) are applied as aqueous-based dispersions which essentially consist of a single polymer selected from the group consisting of acrylic polymers, acrylic copolymers, polyvinyl acetate, polyvinyl alcohol, ethylene-vinyl acetate, polyvinyl chloride, styrene-butadiene copolymers, polyvinylidene chloride and its copolymers or starch, the base layer ( 14 ) and the additional layer ( 16 ) may optionally include thickeners, defoamers or defoamers, crosslinking agents, lubricant additives, mold release agents and anti-blocking agents; and where the base layer ( 14 ) and the additional layer ( 16 ) form a non-porous film on the substrate that is water resistant and has a water vapor transmission rate in the range of 0.8 to 7 g / 645.2 cm ² (100 in ² ) per 24 hours. Use according to claim 1, the dispersions on aqueous Basis have a solids content of more than 20%. Use according to claim 1, the dispersions on aqueous Base a viscosity in the range of 20 to 1000 mPa × s (cP) have. Use according to claim 1, wherein the base layer ( 14 ) dry addition levels in the range of 0.453 to 3.624 kg / 278.71 m ² (1 to 8 lb / 3MSF) on the substrate surface. Use according to claim 1, wherein the additional layer ( 16 ) dry addition levels in the range of 0.453 to 3.624 kg / 278.71 m ² (1 to 8 lb / 3MSF) on the base layer ( 14 ) results. Use according to claim 1, wherein the coatings give a total dry addition in the range of 0.906 to 7.248 kg / 278.71 m ² (2.0 to 16 lb / 3MSF). Use according to claim 1, wherein the paper or cardboard ( 12 ) have a basis weight in the range of 9.06 to 67.95 kg / 278.71 m ² (20 to 150 lbs / 3000 ft ² ) and a thickness in the range of 0.102 to 0.635 mm (0.004 to 0.025 inch). Use according to claim 1, wherein the base layer ( 14 ) consists essentially of acrylic-modified poly (ethyl acrylate) latex, and the additional layer ( 16 ) consists essentially of polyvinylidene chloride or its copolymers. Use according to claim 1, wherein the base layer ( 14 ) and the additional layer ( 16 ) consist essentially of polyvinylidene chloride or its copolymers. Use according to claim 1, wherein the recyclable and re-unlockable coating paper or the recyclable and re-unlockable, coated cardboard further at least one additional layer ( 16 ) include.